Hera Engineering was engaged to undertake the complete structural works of the new Lakelands Train Station with ADCO Construction for the Public Transport Authority. Part of the works for this scope consisted of the concourse pedestrian bridge which facilitates access over the rail corridor with realignment of the overhead line electrification supports. The design had to ensure all works could be carried out within a rail shutdown period and satisfy the Clients design requirements (120-year design life and potential for complete loss of any support due to accidental loading).
In order to satisfy the durability requirements, the permanent design was required to consist of a concrete deck. Conventional deep concrete beams were unable to be provided due to Architectural constraints (in addition, these were required to be lifted from 25m away on a 6m high retaining wall). To maintain structural integrity of a thin concrete deck, it was required to be cast in-situ to permit the installation of post-tensioning to span across the rail line.
The final design solution consisted of a complete modularised steel framed structure with a thin concrete deck suspended to permit the in-situ post-tensioned solution. This thin concrete deck acted as permanent formwork and allowed the reinforcement to be assembled prior to the shutdown.
This complete modularised solution permitted a range of work to be carried out prior to the lift, such as load testing of lifting points, installation of reinforcement for the in-situ deck and testing for overhead line works prior to the shutdown.
Hera Engineering worked with the construction team within the constraints of the industry to provide a solution that could be constructed safely and within the time-constraints given and meeting the Client’s performance requirements. This was fundamental to the success of the works over the rail shutdown and resulted in completing the works 10% earlier than planned.